Cooling system for motor vehicles and method for controlling at least one air mass flow through a radiator

ABSTRACT

Cooling system for motor vehicles with at least one radiator to which in a first operating phase, particularly in the ram pressure phase, a first air stream can be supplied via a first air flow path and which in an alternative or simultaneous second operating phase, particularly during fan operation, can be supplied by means of at least one air-conveying device, with a second air stream flowing along a second air flow path. Among other things, it is also provided that at least in some regions the two air flow paths are oriented at an angle to each other so that the air-conveying device is disposed outside or essentially outside the first air flow path. The invention also related to a corresponding method.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/DE02/02827, filed Jul. 26, 2002 which claims benefit of German patent application number 10137717.7, filed Aug. 1, 2001.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a cooling system for motor vehicles with at least one radiator. The invention also relates to a method for controlling at least one air mass flow through the radiator of a motor vehicle during different operating phases of the vehicle.

In motor vehicles, for example passenger cars or trucks, the cooling of the liquids and gases used therein is carried out by means of appropriate heat exchangers, for example intercoolers, coolant coolers or condensers, which are located at the front end of the motor vehicle, often in a modular unit, namely one behind the other as seen in the direction of forward movement of the motor vehicle.

EP 0 487 098 B1 discloses a cooling system wherein the radiator for the engine of the motor vehicle is located at the end of the cooler module, namely as far from the front end of the motor vehicle as possible. During vehicle movement, an air stream generated by ram pressure at the front end of the motor vehicle flows through the cooling module. To be able to provide the air mass flow necessary for the required cooling action even while the motor vehicle is standing or moving slowly, a centrifugal fan with cap is provided in the air flow path downstream from the radiator for the purpose of creating an air stream flowing through the cooling module. Beyond a certain moving velocity, the air ram pressure at the front end of the motor vehicle is sufficiently high to provide any required air mass flow.

The drawback of the known cooling system is that under operating conditions in which the air mass flow through the cooling module is created by ram pressure at the front end of the motor vehicle, the cover of the fan cap and the fan hub act as resistances increasing the pressure loss caused by the cooling module. Moreover, the fan cap, because of its alignment with the radiator, covers large regions of the same so that the entire air mass flow must pass through the fan opening. This results in nonuniform flow through the radiator which also affects the heat exchanger disposed ahead of it and, in particular, reduces its cooling efficiency. The pressure losses which are present anyway are further increased by the nonuniformity of the air stream.

The object of the invention is to provide a cooling system of the aforesaid kind wherein operating control adaptable to all operating phases is possible and, in particular, a more uniform flow through the radiator is ensured under all moving conditions/operating phases of the motor vehicle. Another object is to indicate a method allowing exact control of at least one air mass flow through the radiator under all movement conditions.

To reach this objective, we propose a cooling system having the features of claim 1. In a first operating phase, the cooling system is cooled by a first air stream along a first air flow path. In a second operating phase, the cooling is produced by a second air stream flowing along a second air flow path. The two air streams can be provided alternatively or simultaneously. Because, at least in some regions, the two air flows are at an angle or across one another in a manner such that the air-conveying device for the second air stream is outside or essentially outside the first air flow path, a separation, in particular, between the ram pressure mode and the fan operation mode is achieved, because two routes have been formed. One route is preferred for ram pressure operation. This concerns the first air flow path which preferably is linear. If in the second operating phase cooling is accomplished with the aid of an air-conveying device, the second air stream path is used which in terms of region is preferably identical to the first air flow path, but which in terms of region also deviates from the first air flow path. In this manner, the air-conveying device is outside or essentially outside the first air flow path, which means that it does not act as a hindrance and, hence, produces no pressure loss in the first operating phase. In this manner, optimally adapted operation control is possible in all operating phases.

According to the invention, the two air flow paths can at least in some regions be separated from each other and cross each other or combine in the radiator region. In some sections, therefore, the two air flow paths are independent of each other, namely the required operating means, for example an air-conveying system, are always assigned to their “own” air flow path. Hence, the case will not be possible in which the air-conveying system will act as a flow hindrance in a “foreign” air flow path. Because the two air flow paths cross each other or combine in the radiator region, both of them serve to provide cooling air to the radiator.

The invention is characterized by the fact that the system for controlling the air flow through the radiator—as seen in the direction of the air flow—is located in the region in which the air flows away from the radiator. In this manner, it is possible to achieve a more homogeneous, or more uniform flow through both the radiator and possibly through another heat exchanger disposed—as seen in the air flow direction—ahead of it over the entire cooling surface thus increasing the cooling efficiency of the radiator and the heat exchanger. It is also advantageous that the pressure loss caused by the radiator, particularly under ram pressure-dominated operating conditions, is reduced. Because the radiator and at least one heat exchanger optionally located ahead of it produce a relatively small pressure loss, the air mass flow through the radiator and the heat exchanger(s) and thus the cooling efficiency are correspondingly high so that for a predetermined, required cooling efficiency the cooling surface can be correspondingly small.

As an alternative, it is also possible to dispose the control system in the region of the air flowing—as seen in the air flow direction—toward of the radiator.

In a preferred embodiment of the invention, the radiator serves to cool the coolant for the engine of a motor vehicle, for example a combustion engine. In addition to the radiator, the cooling system can include at least one additional heat exchanger, for example an intercooler and a condenser of a heating or air-conditioning system. In this case, the additional heat exchanger(s) is (are) preferably disposed—as seen in the direction of the supplied air stream—ahead of the radiator to form, coupled with said radiator, a cooling module constituting a unit, each of the heat exchanger/radiator operating independently of each other.

In a particularly advantageous embodiment of the cooling system, the region of air flow from the radiator is free of devices for producing an air stream. This means that the cooling system, unlike the known cooling systems, is devoid of a centrifugal fan with an accompanying cover/cap so that a cooling system of small depth is realizable. According to a further embodiment of the invention, the region of air flow toward the radiator is also free of blowers, fans and the like intended to produce an air flow through the radiator. Hence, neither ahead of nor behind the radiator is there provided a device for creating an air flow so that a particularly uniform air flow can be ensured at least through the radiator.

In a preferred embodiment of the invention, the radiator is disposed in the front end region of the motor vehicle. In the outer wall of the motor vehicle, there is provided at least one air inlet through which the air stream created by ram pressure during the movement of the motor vehicle is supplied to the radiator or the cooling module, said air inlet preferably being disposed in the front end of the motor vehicle. In this arrangement of the radiator in the motor vehicle, said radiator—as seen in the direction of forward movement—is disposed ahead of the engine. In another embodiment, the radiator is disposed in the back end of the motor vehicle, in which case the air inlet can be provided in a side wall of the motor vehicle.

In another embodiment of the invention, the system for controlling the air stream (first air stream) is a covering device capable, in a manner adjustable as a function of the desired operating phase, of freeing, particularly essentially freeing, partly covering or at least essentially covering and particularly completely covering the cross-section of the first air flow path. Depending on the operating phases, it is therefore possible to reduce more or less the cross-section of the first air flow path or even completely close off said cross-section or to increase said cross-section gradually until the complete cross-section has become available. This closing or opening can be controlled in stepless or stepwise manner. The covering system can be controlled and made to take the required position depending on the desired operating phase. A suitable actuator is provided for this purpose.

Preferably, the covering device has at least one swiveling flap. Alternatively or additionally, the covering device can also have several flaps preferably disposed in the manner of a louver. By this is meant a flap arrangement in which several flaps have parallel rotational axes, said rotational axes being disposed so close together that in the closed position the ends of adjacent flaps lie on top of each other thus providing coverage in the manner of a louver. Depending on the open position of the flaps, the cross-section of the air flow path is freed to a variable extent.

Also preferred is a cooling system characterized in that the system for controlling the first air stream has, in particular, several swivelable flaps assigned to the first air flow path, capable of taking several positions and freeing the first air stream in a first position and closing it off, at least partly but preferably completely, in a second position. The preferably lamellar flaps are preferably so optimized from a flow standpoint that in their first position in which they free the air flow path they do not affect the air flow through the radiator practically at all, or at least affect it only to a minor extent such that the resulting pressure loss is therefore not significant. In other words, the design of the flaps and their arrangement in the freeing position is such that the entire cooling surface is uniformly exposed to, and homogeneously contacted by, the air stream.

In place of or in addition to the said flaps, it is also possible for the covering device to have at least one adjustable roller blind. Depending on the position of the roller blind, the assigned air flow path is more or less covered/closed. To prevent the air pressure from swinging the roller blind out excessively, an air-permeable support, particularly a supporting grille, is preferably provided. The roller blind can assume a flat position on the support and thus not be displaced to an unacceptable extent even at higher air pressures. The air-permeable support has an adequately fine-meshed structure so that it does not affect the air flow or affects it only to a negligible extent.

According to another embodiment of the invention, the covering system leaves toward the radiator a free space to allow the formation of at least part of the second air flow path. During the first operating phase, the first air stream also passes through this free space so that said first air stream can flow over the cooling surface unhindered. When the second operating phase takes place, the covering device closes thereby limiting the free space. However, because the covering device is disposed at a distance from the radiator, the second air stream can bring about the cooling of the radiator by being blown into the free space at an angle to the direction of the aforesaid first air stream and/or sucked out of the free space so that—for example, in the case of suction—the sucked-out air of the second air stream passes through the radiator, reaches the free space and now, because of the covering device being closed, can flow off in a direction vertical to the radiator surface, to cool, in particular, the combustion engine of the motor vehicle, but because the covering device is closed, it leaves the free space laterally. This lateral exiting allows the installation of an air conveying device laterally to the radiator so that the first air flow path remains undisturbed, namely so that the flow is not hindered. The wording “installation of an air-conveying device laterally to the radiator” means that the first air flow path contains no hindrances. The air-conveying device, however, can also assume positions other than the lateral one if it is connected via an appropriate air-guiding tube or the like to the lateral surfaces or at least one lateral surface of the free space. In such a case, too, it is necessary to make sure that the air-conveying device is not causing a hindrance in the first air flow path.

It is possible, in particular, to provide for the formation of the free space an air-conveying box containing the covering device the covering action of which is assigned to a flow cross-section for the first air stream. In particular, at least one air inlet and/or at least one air outlet for the second air stream is provided laterally. Preferably, the cross-section of at least one air inlet and/or air outlet for the second air stream is disposed at an angle, particularly at a right angle, to the flow cross-section of the first air stream.

To reduce the pressure losses during suction or blowing, it is possible to enlarge the cross-section of the second air flow path in the region of the air inlet and/or air outlet, In particular, the said air-conveying box can be shaped as a frame, with the covering device located on the frame. In accordance with the increase in cross-section in the region of the air inlet and/or air outlet, the depth of the frame at the air inlet and/or air outlet is larger than in the other regions of the air-conveying box. The flap, the flaps, the roller blind and/or the roller blinds are thus preferably disposed on the frame.

Other advantageous embodiments of the cooling system are indicated by the other subclaims.

To reach the objective, we also propose a method for controlling at least one air mass flow through the radiator of a motor vehicle during the various operating phases of the motor vehicle, said method having the features indicated in claim 36. According to this method, during the first, ram pressure-dominated operating phase of the motor vehicle, namely during a forward movement of the motor vehicle at a sufficiently high speed at which a desired ram air pressure is created at the font end of the motor vehicle, a first free air stream is supplied to the radiator through at least one air inlet provided in the outer wall of the motor vehicle, said air stream flowing through the radiator from the front end thereof. By “free air stream” is meant that said stream is created exclusively as a result of the ram pressure prevailing at the front end. During this operating phase, any required air mass flow through the cooling module or through the radiator can be made available. Moreover, by said method it is possible that during the second operating phase of the motor vehicle, namely when said vehicle is standing or when it moves at low speed, the air flow path, especially in the region of air flow away from the radiator, is blocked in a suitable manner, and a second air stream created in a part of the motor vehicle lying outside the air flow path is sucked through the radiator. The method is characterized in that in every moving condition of the motor vehicle, exact control of the air mass flow through the radiator is possible without the need for a flow-disturbing blower being located in regions of air flow to and/or from the radiator.

Also preferred is an embodiment of the method of the invention which is characterized in that during the cold-starting phase of the motor vehicle, the air flow path in the regions of air flow from or toward the radiator is blocked, and no air is sucked or blown through the radiator. The blocked air flow path causes the air to dam up at the radiator, or not to reach the radiator, so that the cooling efficiency of the radiator is only minimal. In this manner, rapid heat-up of the cooling medium flowing through radiator is achieved.

Other advantageous embodiments of the method of the invention are indicated by the other sub-claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a schematic representation of a section of an embodiment of the cooling system of the invention;

FIG. 2 is a view in perspective of a first embodiment of a cover equipped with swiveling flaps or a covering device for a radiator with the flaps in the air flow-freeing position;

FIG. 3 is a view in perspective of the cover of FIG. 2 with the flaps assuming the stopping/blocking position;

FIG. 4 is a view in perspective of a second embodiment of the cover;

FIG. 5 is a view in perspective of the cover of FIG. 4 and showing the flap arrangement;

FIG. 6 is a view in perspective of a third embodiment of the cover;

FIG. 7 is a cross-section of a second embodiment of the radiator with a fourth embodiment of the cover;

FIG. 8 is a cross-section of a third embodiment of the radiator with a fifth embodiment of the cover;

FIG. 9 is a view in perspective of another covering device;

FIG. 10 is a variant of an embodiment of the covering device of FIG. 9;

FIG. 11 is a modified version of the covering device of FIG. 10;

FIG. 12 is another modification of the covering device;

FIG. 13 is also another modification of a covering device;

FIG. 14 is a view in perspective of an air flow-creating device designed in the form of a blower;

FIG. 15 shows an air conveyor between the radiator, particularly the radiator cover frame, and the blower;

FIG. 16 shows another embodiment of an air conveyor;

FIG. 17 is a view of the air conveyor of FIG. 15 along the longitudinal axis of a motor vehicle equipped with a cooling system;

FIG. 18 is a top view of the representation of FIG. 17;

FIG. 19 is a view, in the direction of the longitudinal axis of the motor vehicle, of an air conveyor according to another embodiment according to FIG. 16, and

FIG. 20 is a top view of the air conveyor of FIG. 19.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Cooling system 1 described in the following can be used generally for motor vehicles 3, for example passenger cars, trucks, buses and the like, having as an engine, for example, a combustion engine. Cooling system 1 can readily be used also in electric vehicles or hybrid vehicles.

FIG. 1 shows a schematic diagram of an embodiment of cooling system 1 disposed in front end 5 of motor vehicle 3, shown with broken lines, in a motor space 7. During forward movement, motor vehicle 3 moves in the direction from right to left of FIG. 1, as indicated by arrow 8. Cooling system 1 or a component thereof is located in the space between a combustion engine 9 and an outer wall 11 forming the vehicle front. In the outer wall 11 is provided a wall opening 13 forming air inlet 12 in which opening is disposed an air-conveying device 15 the function of which is to supply to cooling system 1, during the movement of motor vehicle 3, a first air stream 53, here moving in horizontal direction indicated by arrows, along a first air flow path 57. This will be discussed in greater detail in the following.

Here, cooling system 1 comprises a first heat exchanger 17 consisting of a radiator 19 for cooling the coolant for the combustion engine, for example water. Radiator 19 has a connector 21 through which the coolant enters radiator 19 and at least one other connector, not shown in the representation of FIG. 1, through which the coolant is recycled to combustion engine 9. The design and the function of radiator 19 are generally known and do not require additional discussion here. It is to be kept in mind that radiator 19 can be exposed to air stream 53 introduced through air inlet 12, as indicated by the arrows referring to first air flow path 57, the first air stream 53 entering at the front side 23 of radiator 19 and exiting at the opposite, back side 25 of the same without being deflected in radiator 19. This means that first air stream 53 flowing toward radiator 19 in horizontal direction and essentially vertical to radiator front 23 passes through radiator 19 in a straight line and again exits at the radiator back side 25 while maintaining its horizontal orientation.

On the side opposite combustion engine 9, in the region between air inlet 12 and radiator 19, there is disposed in the first air flow path 57 another heat exchanger 26, for example an intercooler or a condenser of an air-conditioning unit through which first air stream 53 is introduced into motor space via air inlet 12 or which in this embodiment of heat exchanger 26 flows through this space, as indicated by arrows in FIG. 1. Heat exchanger 26 and radiator 19 can be coupled to form a cooling module (not shown) which can be preassembled. Cooling system 1 can be provided with additional heat exchangers besides those shown in FIG. 1, all such additional heat exchangers preferably being disposed between outer wall 11 and radiator 19. In the preferred embodiment, the space between radiator 19 and combustion engine 9 is free of devices for creating an air flow through radiator 19 or through the cooling module and of heat exchangers of cooling system 1 so as to ensure that the free flow of the air stream leaving the radiator backside 25 is not hindered.

Moreover, cooling system 1 is provided with a device 28 for controlling the air stream flowing through radiator 19 and which has a cover/covering device 27 disposed on the radiator back side 25. Preferably, covering device 27 is combined with radiator 19 to a preassemblable unit. Covering device 27 comprises a frame 29 which, as shown in FIG. 2 which is a view in perspective of the covering device 27 shown in FIG. 1, has in this embodiment, as can be seen, the shape of a rectangle corresponding in size and shape to the radiator surface on the radiator back side 25. Frame 29 consists of frame parts 29.1, 29.2, 29.3 and 29.4. Each of frame parts 29.1 and 29.2 is provided with two elongated, preferably flow-optimized flow-through openings 31 forming cross-section 63 of an air outlet and to which is connected a device, not shown, for creating an air stream, said device—seen in the direction of forward movement 8 of motor vehicle 3—being disposed laterally relative to radiator 19. For this purpose, the air stream-creating device comprises at least one blower, particularly a suction fan, for example a centrifugal fan. To each of the flow-through openings 31 is connected suction tube 33, FIG. 2 showing only one of such tube. By means of suction tube 33, the air can be removed from motor space 7 in a specific manner, particularly through radiator 19. Suction tube 33 can consist, for example, of a hose, particularly a flexible hose, or of a channel with rigid side walls.

Covering device 27 also comprises a number of flaps 35 attached to frames 29 and which run parallel to each other, each flap being able to swivel about an axis 37 that is vertical to the plane of the drawing. To this end, each flap 35 is provided at its end with a pivot pin/bearing pin located in corresponding openings in lateral frame parts 29.1 and 29.2, and each of which is aligned with a flow-through opening 31 allocated to a flap 35. Flaps 35 are disposed within the region of air flow away from radiator 19 and can swivel into several positions.

In an embodiment not represented in the figures, swivel axes 37 of flaps 35 are oriented parallel to frame parts 29.1, 29.2. Basically, any arrangement of flaps 35 on cover 27 is possible. It is important that the region of air flow away from the radiator can be, at least essentially partly and preferably completely, closed off.

In FIGS. 1 and 2, flaps 35 are swiveled into a first position in which they free the air flow path in the region of flow away from radiator 19 in a manner such that the first air stream 53 uniformly flowing through radiator 19 is not affected, namely blocked or diverted. In this manner, it is ensured that covering device 27 will produce practically no pressure loss, that the air stream will impinge uniformly on the entire radiator surface and that said surface will be exposed at least essentially to uniform flow.

In FIG. 3, the flaps are shown to have swiveled into a second position in which the first air flow path 57 in the region of flow away from radiator 19 is completely closed off or blocked. This means that covering device 27 causes first air stream 53 to be dammed up behind radiator 19—as seen in the direction of flow of first air stream 53—so that said stream can no longer flow off freely.

As can be seen from FIGS. 1 to 3, flaps 35 when swiveled into the closing position (FIG. 3) define between the covering device/cover 27 and the radiator back side 25 a free space 39 which on its periphery is completely closed toward motor space 7 by frame parts 29.1, 29.2, 29.3 and 29.4. The gap between radiator 19 and frame 29 in the region where they are connected to each other can optionally be sealed by means of a suitable seal, not shown, so as to prevent any air flow from motor space 7 into free space 39.

Flow-through openings 31 in frame parts 29.1 and 29.2 are disposed in the space between flaps 35 and the radiator back side 25 so that a negative pressure can be applied to free space 39 by means of the air flow-creating device. In this manner, when flaps 35 are closed, a defined, preferably adjustable second air stream 55 can be aspirated along a second air flow path 59, via the cooling module, namely heat exchanger 26 and radiator 19, as indicated by arrow 41 in FIG. 2.

In the embodiment of covering 27 shown in FIGS. 1 to 3, flaps 35 attached to it in swivelable manner are appropriately force-coupled to each other and can be actuated automatically by a positioning device that is not shown. To this end, the positioning device is provided with a suitable drive or is coupled with the drive of another device of motor vehicle 3. Control of the flap actu-ation is brought about by a control/regulation device of cooling system 1, not shown. In other words, all flaps 35 are swiveled together into the closing-off position and into the flow-release position. According to an advantageous variant of the embodiment, the drive of the positioning device for flaps 35 swivels said flaps into their closing-off position (FIG. 3), the restoration into the flow-release position occurring in spontaneous manner by means of a spring element, namely when the ram pressure of the first air stream 53 falls below a certain level. It is, of course, also possible for all flaps 35 to be swiveled into the closing-off as well as into the flow-release position by means of the drive of the positioning device.

Cover 27 shown in FIGS. 1 to 3 has only minor, space-saving depth. It should be kept in mind, however, that between cover 27 and combustion engine 9 no structural elements are present that would affect the air flow through radiator 19 so that the air stream leaving radiator back side 25 impinges on combustion engine 9 and optionally flows around it.

The method of the invention for controlling the air mass flow through radiator 19 during the different operating phases or movement conditions of motor vehicle 3 can readily be understood from the description of FIGS. 1 to 3. As can be seen, during the first operating phase of motor vehicle 3, namely during forward movement and above a certain, predetermined speed, a first free air stream 53 created by ram pressure flows through radiator 19 via an air inlet 12, said air stream flowing through front end 23 of radiator 19. To this end, flaps 35 disposed within the first air flow path 57 in the region of flow away from radiator 19 are swiveled into their flow-release position (FIGS. 1 and 2). In this position, in which flaps 35 are oriented in the first air flow path 57 with their narrow side oriented in the direction of air flow thus offering practically no resistance to the first air stream 53 flowing through radiator 19, the flow through said radiator is uniform. It is also advantageous that, as a result of the absence of structural elements in first air flow path 57, the air mass flow through radiator 19 in the region of flow away from the radiator is, even at relatively low speeds of motor vehicle 3, so high that any required cooling efficiency can be realized. During a second operating phase of motor vehicle 3, in which said vehicle is standing or is moving at low forward speed, flaps 35 are swiveled into their closing-off position in which they completely block first air flow path 57 in the region of flow away from radiator 19. With the aid of the air-flow creating device disposed ouside first air flow path 57, a second, adjustable air stream 55 is sucked through radiator 19 along second air flow path 59 so that even under vehicle movement conditions not dominated by ram pressure an air mass flow required to achieve the desired cooling efficiency passes through radiator 19. In the region of air flow toward radiator 19, the two air flow paths 57 and 59 are formed equal, at least in some sections. In the region of air flow away from radiator 19, the two air flow paths 57 and 59 are different.

As a result of cover 27 being disposed between radiator 19 and combustion engine 9, there is provided the advantageous possibility of accelerating the warming of the coolant flowing through radiator 19 during the cold start-up phase. To this end, flaps 35 are swiveled into their blocking/closing-off position thus closing off first air flow path 57. Moreover, during the cold start-up phase no air is removed from free space 39 by suction. The air is thus dammed up at radiator 19 which as a result shows correspondingly low cooling efficiency. In this manner, the coolant is warmed up more rapidly.

FIG. 4 depicts a second embodiment of cover 27, with flaps 35 not showing, and which differs from cover 27 described with the aid of FIGS. 1 to 3 particularly in that additional frame parts 29.5 and 29.6 are provided between frame parts 29.1 and 29.2 that form the side walls of cover 27, said additional frame parts being disposed parallel to frame parts 29.1 and 29.2. As can be seen from FIG. 5, a first number of flaps 35.1 is held in swivelable manner at frame parts 29.1 and 29.6, a second number of flaps 35.2 is held at frame parts 29.6 and 29.5, and a third number of flaps 35.3 is held at frame parts 29.5 and 29.2. Flaps 35.1 to 35.3, each allotted to a partial region of the radiator surface are swivelable independently of each other so that only parts of cover 27 can be closed and the air flow path is only partly blocked. It is thus possible for the air mass flow over the cooling module to consist of a combination of ram pressure flow and suction via flow-through openings 31.

In FIG. 5, flaps 35.2 located in the central region of the air flow path are swiveled into their flow-release position whereas flaps 35.1 and 35.3 located outside are closed thus blocking the air flow path in these regions. In this embodiment, the radiator surface covered by flaps 35.2 is greater than the radiator surface coverable by means of flaps 35.1 and 35.2. To this end, flaps 35.3 are correspondingly longer. When all flaps 35.1 to 35.3 are swiveled into their closing-off position, the air flow path is completely blocked. Naturally, flaps 35.1 to 35.3 can have lengths other than those shown in the figures.

As indicated in FIG. 4, a suction channel 43 is integrated into each of frame parts 29.5 and 29.6, said channel penetrating the upper frame part 29.3 and being attachable to the device for creating suction flow. Suction channels 43 are connected to free space 39 via openings 45. The additional frame parts 29.5 and 29.6 also improve the rigidity of cover 27.

FIG. 6 depicts another embodiment of cover 27, with flaps 35 not shown. Cover 27 differs from covers 27 described by way of FIGS. 4 and 5 in that in the middle between frame parts 29.1 and 29.2 there is present only one additional frame part 29.5 which is provided with a suction channel 43. Between frame parts 29.1 and 29.5 is held in swivelable manner a first number of flaps and between parts 29.5 and 29.2 a second number of flaps, as in the embodiment depicted in FIG. 5, said flaps being swivelable independently of each other so that, if necessary, only parts of cover 27 can be closed off.

It should be kept in mind that cover 27 can readily also be designed so that more than three partial regions can be closed or opened independently of each other. In the embodiment described with the aid of FIGS. 4 to 6, these partial regions are disposed next to each other—as seen in the direction of air flow—and extend over the entire height of the air flow path. Naturally, it is also possible to design cover 27 so that in at least one partial region, flaps 35 disposed therein are swivelable so that only a section of this partial region is closed off, whereas the flaps disposed in another section of this partial region are in the flow-release position.

If in the embodiment of cover 27 described with the aid of FIGS. 4 to 6 the swivel axes 37 of flaps 35 are parallel to frame parts 29.1, 29.2, the additional frame part 29.5 or parts 29.5 and 29.6 may be omitted. Even so, it is quite possible for some of flaps 35 to be made to move independently of each other so that, for example, only certain parts of the region of flow away from the radiator are closed while other flaps are disposed in the air flow path in a manner such that the air can flow between flaps 35. Compared to the above-described embodiments, this embodiment of cover 27 has a reduced number of parts.

FIG. 7 shows a schematic representation of a further embodiment of radiator 19 and cover 27 in cross-section. Identical parts are identified by the same reference numerals, the reader therefore being referred to FIGS. 12 to 6. Radiator 19 has a curved shape, the curvature being oriented in the direction of forward movement 8 of motor vehicle 3. On radiator back side 25 there is provided cover 27 whose frame 29 is adapted to the shape of radiator 19 or to the radiator surface disposed in the air flow path thus being exposed to the air stream. As can be seen, in this form of radiator 19, too, small structural depth is realizable. This would not be possible if a centrifugal fan were located in the region of air flow away from the radiator as is the case in known cooling systems.

In an embodiment deviating from that represented in FIG. 7, other curved shapes of radiator 19 are also possible, for example any free forms allowing an optimum, preferably space-saving placement of radiator 19 in motor space 7 that is ideally adapted to the available space. The curved radiator and the cover adapted to the shape of the radiator can also be at an angle to the longitudinal extension of the motor vehicle. Other arrangements are also possible.

FIG. 8 shows a schematic representation of a third embodiment of radiator 19 and cover 27 in cross-section. Parts that have already been described with the aid of the foregoing figures are indicated by the same reference numerals. Radiator 19 has a wedge-shaped contour with the tip of the wedge pointing in the direction of forward movement 8 of motor vehicle 3. Frame 29 of cover 27 that is disposed on the radiator back side 25 is adapted to the shape of radiator 19 and it, too, is wedge-shaped. This is achieved by disposing lateral frame parts 29.1 and 29.2 at an appropriate angle. This design, too, has only a small structural depth. The orientation of the radiator and of the cover can be chosen so that during forward movement of the motor vehicle the tip of the wedge is directed in the direction opposite to that of forward movement, namely in a direction that is exactly opposite to that shown for the embodiment represented in FIG. 8.

Flaps 35 of cover 27 shown in FIGS. 7 and 8 can be swiveled about an axis 37 that is vertical to the plane of the drawing and parallel to an imagined horizontal axis. In FIGS. 7 and 8, these flaps are swiveled into their flow-release position. In the closing-off/blocking position, flaps 35 are not disposed vertical to the air flow through radiator 19 as is the case in the embodiment described with the aid of FIGS. 1 to 3, but at an angle. Complete blocking of the first air flow path 57, optionally by appropriately curved flaps 35, can still be ensured.

In the embodiment represented in FIG. 9 is shown a covering device 27 built in the form of a frame and which in the region of each of its vertical sides 65, 67 is provided with roller blind box 69, 71. From roller blind box 69, 71, roller blinds 73, 75 can be pulled out in the direction toward one another or they can be pulled out by means of a suitable drive system. This can be done in stepless manner. Consequently, the size of flow-through cross-section 77 of first air flow path 57 can be adjusted in accordance with the positions of roller blinds 73, 75. Toward the radiator, not shown, roller blinds 73, 75, for the purpose of forming a free space, are disposed at a distance from each other so that in the region of the two sides 65 and 67 cross-sections 79 and 81 of the second air flow path are formed. The operation during use is the same as the operation of a covering device 27 provided with flaps so that this aspect does not need further discussion.

The embodiment of FIG. 10 also shows a covering device equipped with roller blinds 73, 75 but differing from that of FIG. 9 in that there is provided an air-permeable support 83 in the form of a support grille 85. Support 83 is located downstream from the corresponding roller blinds 73, 75 preventing said blinds 73, 75 from being deformed or moved by the air pressure.

The embodiment of FIG. 11 shows a covering device 27 that greatly resembles that shown in FIG. 10. The difference consists in that in the region of sides 65 and 67 cross-sections 79 and 81 become wider with increasing distance from the center of covering device 27, which results in unusually low pressure losses. In the case that a second air stream is created by suction, the pressure losses during suction are reduced and the surface intended for suction is enlarged because of the smaller structural depth of the air conveyor at the sides of device 28. This widening of the cross-section can occur by appropriate inclination—as seen in longitudinal cross-section—of the corresponding surfaces. It is also possible, however, to use circle segments of appropriate radii.

The embodiment of FIG. 12 takes into consideration the recently issued Pedestrian Protection Decree for which it may be necessary for radiator 19 to be lower or to be placed at an angle. This embodiment meets the requirements of this decree in that the support grille and/or the opened cover, not shown in detail, for example the roller blinds, are disposed in a vertical plane while radiator 19 is inclined. As a result, a free space 39 is formed which decreases in the upper part of its depth while becoming gradually larger toward the bottom. Correspondingly, cross-section 79 is then also located at the bottom to create second air flow path 59 for second air stream 55.

FIG. 13 shows a covering device 27 in which, in relation to the direction of first air stream 53, radiator 19 is located downstream from covering device 27. This means that the incoming first air flow 53 first reaches free space 39 (provided the cover is closed) and then passes through radiator 19. If the cover is closed, there is preferably provided an air stream-creating device that does not aspirate but blows, meaning that it blows sideways into free space 39 so that radiator 19 is supplied with cooling air from free space 39. This air passes through the radiator and then preferably reaches the adjacent combustion engine 9 (not shown).

FIG. 14 shows a blower 88 constituting the air flow-creating device consisting of several structural components. Blower 88 shown in this figure is designed as a tube fan 89 that is provided with a constant-pressure impeller followed by a guide wheel. For simplicity, FIG. 14 does not show the housing enveloping said wheels.

Alternatively, a centrifugal fan (not shown) can also be used as blower 88. For both the said centrifugal fan and the said tube fan, the impeller diameter amounts to about 30 to 60% of the vertical dimension of the radiator, particularly the vertical dimension of the radiator core (active elements of the radiator).

Blower 88 can be either a blowing or a sucking fan.

Blower 88 or the fan are preferably installed laterally or essentially laterally relative to radiator 19. The orientation of the air flow thus created is either parallel or at right angles to the longitudinal axis of a motor vehicle equipped with cooling system 1. An intermediate angle between this parallel or right-angle orientation and including the flow toward the longitudinal axis of the motor vehicle is also conceivable.

FIGS. 15, 17 and 18, on the one hand, and FIGS. 16, 19 and 20, on the other, show air conveyors of different structural design. In the embodiment of FIGS. 15, 17 and 18, the air flow is at right angles to the longitudinal axis of the motor vehicle whereas for the air conveyor in the embodiment of FIGS. 16, 19 and 20 said air flow is parallel to the longitudinal axis of the motor vehicle. FIGS. 15 and 20 show air conveyors 90 with a blower seat for only one half of radiator 19. Air conveyor 90 is located between radiator 19 or the radiator cover frame and blower 88 and is designed as a special channel. FIGS. 15 to 20 show cover 27 allocated to radiator 19, from which cover air conveyor 90 originates. From the aforesaid figures, it can be seen that air conveyor 90, designed as a channel, is always located in the lower region of cover 27. Alternatively, it is, of course, also conceivable to locate said conveyor in the middle or in the upper region. It can also be seen from the said figures that only one channel is allocated to a cover 27. Naturally, it is also conceivable for several channels to lead to a cover 27, in which case one blower is assigned to several channels or one blower is assigned to each channel. To be able to orient the channel in the direction of the longitudinal axis of the motor vehicle, in the embodiment of FIGS. 16, 19 and 20 there is provided a deflecting zone for the air flow. In the embodiments of FIGS. 15, 17 and 18, this deflection is not necessary, because the channel is oriented across the longitudinal axis of the motor vehicle.

In all embodiments, with regard to the channel for air control between the radiator cover and the fan/blower, it is possible to provide at least one device, particularly guide baffles, to improve the flow.

It is also possible to provide after the blower/fan a flow channel or several flow channels to be able to undertake specific control of air flow out of the motor space of the motor vehicle. This additional flow channel or these additional flow channels downstream from the fan/blower can also be used to direct air toward specific components of the motor space. 

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 39. Cooling system for motor vehicles with at least one radiator to which, in a first operating phase and particularly in the ram pressure phase, a first air stream can be supplied via a first air flow path and which in an alternative or simultaneous second operating phase, particularly during fan operation, can be supplied by means of at least one air-conveying device with a second air stream flowing along a second air flow path, wherein the two air flow paths are at least in some regions oriented at an angle to each other and that the air-conveying device is located outside or essentially outside the first air flow path.
 40. Cooling system according to claim 39, for motor vehicles with at least one radiator to which in a first operating phase, particularly in the ram pressure phase, a first air stream can be supplied via a first air flow path and which in an alternative or simultaneous second operating phase, particularly during fan operation, can be supplied by means of at least one air-conveying device with a second air stream flowing along a second air flow path, wherein the two air flow paths are at least in some regions separated from each other and cross or combine in the radiator region.
 41. Cooling system according to claim 39, for motor vehicles with at least one radiator, for example for a combustion engine, whereby an air stream (first air stream) can be supplied to the radiator via at least one air inlet provided in the outer wall of the motor vehicle, and with a device for controlling the air stream flowing through the radiator, the control device being located in the region of air flow away from the radiator—as seen in the direction of the air stream.
 42. Cooling system particularly according to claim 39, for motor vehicles with at least one radiator, for example for a combustion engine, whereby an air stream (first air stream) can be supplied to the radiator via at least one air inlet provided in the outer wall of the motor vehicle, and with a device for controlling the air stream flowing through the radiator, the control device being located in the region of flow toward the radiator—as seen in the direction of the air stream.
 43. Cooling system according to claim 39, wherein the region of flow away from the radiator is free of devices for creating an air stream.
 44. Cooling system according to claim 39, wherein the radiator is located in the front end region or in the back end region of the motor vehicle.
 45. Cooling system according to claim 44, wherein—as seen in the direction of forward movement of motor vehicle—the radiator is disposed in front of the engine of the motor vehicle.
 46. Cooling system according to claim 39, wherein the device for controlling air flow (first air stream) is a covering device capable, in a manner adjustable as a function of the desired operating phase, of freeing, particularly essentially freeing, partly covering or at least essentially covering and, particularly, completely covering the cross-section of the first air flow path.
 47. Cooling system according to claim 39, wherein the covering device is provided with at least one swivelable flap.
 48. Cooling system according to claim 39, wherein the covering device is provided with several flaps preferably arranged as in a louver.
 49. Cooling system according to claim 39, wherein the device for controlling the first air stream is provided with several flaps disposed in the first air flow path and adjustable to several positions, said flaps freeing the first flow path in a first position and closing off said flow path at least partly and preferably completely in a second position.
 50. Cooling system according to claim 39, wherein when the flaps are swiveled into the first position, the first air stream passes through the entire radiator surface uniformly or essentially uniformly.
 51. Cooling system according to claim 39, wherein a first number of flaps is allotted to a first partial region and at least a second number of flaps is allotted to at least a second partial region of radiator, and that the first and second number of flaps can be moved/closed independently of each other.
 52. Cooling system according to claim 39, wherein at least some of the flaps run parallel to each other and can be swiveled preferably about a parallel or essentially parallel imagined horizontal or vertical axis.
 53. Cooling system according to claim 39, wherein a positioning device for automatic movement is allotted to at least some of flaps.
 54. Cooling system according to claim 39, wherein the positioning device is provided with at least one spring element and/or magnetic element whereby at least some of flaps are moved spontaneously into their closing-off position when the ram pressure, particularly that of the first air stream, is below a predetermined value.
 55. Cooling system according to claim 39, wherein the covering device consists of at least one adjustable louver.
 56. Cooling system according to claim 39, wherein the covering device consists of at least two louvers which on closing can be adjusted in relation to each other.
 57. Cooling system according to claim 39, wherein to the louver (each louver) is allotted an air-permeable support, particularly a support grille.
 58. Cooling system according to claim 39, wherein the covering device leaves toward the radiator a free space for the creation of at least part of the second air flow path.
 59. Cooling system according to claim 39, wherein to form the free space there is provided an air-conveying box with the covering device, the cover of which is assigned to a flow cross-section for the first air stream.
 60. Cooling system according to claim 39, wherein laterally relative to the flow cross-section there is disposed at least one air inlet and/or at least one air outlet for the second air stream.
 61. Cooling system according to claim 39, wherein the cross-section of the air inlet and/or air outlet for the second air stream is oriented at an angle, especially at a right angle, to the flow cross-section of the first air stream.
 62. Cooling system according to claim 39, wherein the cross-section of the second air flow path increases with increasing distance from the air inlet and/or air outlet.
 63. Cooling system according to claim 39, wherein the flap, the flaps, the louver and/or the louvers is/are disposed in a frame.
 64. Cooling system according to claim 39, wherein the frame and the flap attached to it and/or at least one louver attached to it form a structural unit which is designed and disposed in a manner such that they form a cover for the—as seen in the flow direction of the first air stream—the back side of the radiator.
 65. Cooling system according to claim 39, wherein a free space between the cover and the back side of the radiator is defined when at least one flap is placed into the closing-off position, and/or at least one louver blind is placed into the closing-off position, the periphery of said free space being at least partly, and preferably completely closed.
 66. Cooling system according to claim 39, wherein the frame preferably consists of several frame parts and that on the frame, preferably on at least one of the frame parts there is provided at least one flow-through opening for connection to a device for creating an air flow (second air stream), the said device preferably being disposed laterally relative to the radiator.
 67. Cooling system according to claim 39, wherein the air flow-creating device is provided with at least one blower to supply air to the free space between the cover and the back side of the radiator at negative pressure or high pressure, or to supply air to the free space between the cover and the front side of the radiator when the blower is blowing.
 68. Cooling system according to claim 39, wherein the radiator has a curvature when seen in cross-section.
 69. Cooling system according claim 68, wherein the curvature is partly circular.
 70. Cooling system according to claim 69, wherein the curvature or rounding of the radiator points in the direction of forward movement of the motor vehicle or in the opposite direction.
 71. Cooling system according to claim 39, wherein the radiator—as seen in cross-section—shows a wedge-like contour, the wedge tip pointing in the direction of forward movement of the motor vehicle or in the opposite direction.
 72. Cooling system according to claim 39, wherein the shape of the frame is adapted to the shape of the radiator or to the radiator surface disposed in the first flow path and exposed to the first air stream.
 73. Cooling system according to claim 39, wherein the radiator is part of a cooling module consisting of several heat exchangers, the other heat exchanger/heat exchangers being disposed ahead of the radiator, as seen in the direction of forward movement of the motor vehicle.
 74. Method for controlling at least one air mass flow through a radiator for a motor vehicle during different operating phases of the motor vehicle, said method comprising the following steps: during a first operating phase, through an air inlet preferably located in the outer wall of the motor vehicle, there is supplied a first, free air stream which flows through the radiator, particularly from the front side thereof, and during a second operating phase of the motor vehicle the first air flow path is blocked in the region of flow away from the radiator and a second air stream created in a part of the motor vehicle lying outside the first flow path is blown and/or sucked through the radiator.
 75. Method according to claim 74, wherein during the cold-starting phase of the motor vehicle the first air flow path is blocked in the region of flow away from or toward the radiator, so that no more air is sucked or blown through the radiator.
 76. Method according to claim 74, wherein the volume of the first air stream flowing through the radiator can be controlled—preferably in stepless manner. 